厦门杏林湾水库底泥有机质和营养盐的分布特征与来源及污染评价

Distribution Characteristics,Sources and Pollution Evaluation of Organic Matter and Nutrient Salts in Sediment of Xinglin Bay Reservoir in Xiamen City

以厦门杏林湾水库为研究对象,测定表层底泥中有机质(OM)、总氮(TN)、游离态氮(FN)、可交换态氮(EN)、酸解态氮(HN)、残渣态氮(RN)、总磷(TP)、有机磷(OP)、无机磷(IP)、铁铝结合态磷(NaOH-P)和钙结合态磷(HCl-P)的质量比,分析表层底泥中有机质及营养盐的分布特征和污染状况。结果表明:杏林湾水库底泥中OM,TN和TP的平均质量比分别为49360.28,1588.63,1095.63 mg·kg^(-1);OM,TN,EN和HN的空间分布呈现从后溪汇入处至入海口处先增加后减小、从九天湖排洪渠和董任排洪渠交汇处至入海口处逐渐减小的特征;TP,IP,NaOH-P和HCl-P的空间分布呈现随水流方向逐渐减小的特征;底泥具有较高氮磷释放风险,易发生富营养化问题,其中,氮主要来源于有机质富集,磷主要来源于上游支流及周边地区含磷农业废水和居民生活污水,OM主要来源于高等植物;氮、磷单项污染指数和综合污染指数整体上均处于重度污染,营养盐污染主要来源于氮,有机指数整体处于尚清洁水平,且底泥整体受到有机氮污染。

Taking Xinglin Bay Reservoir in Xiamen City as the research object,the mass ratios of organic matter(OM),total nitrogen(TN),free nitrogen(FN),exchangeable nitrogen(EN),acid solution nitrogen(HN),residual nitrogen(RN),total phosphorus(TP),organic phosphorus(OP),inorganic phosphorus(IP),iron/aluminum combined phosphorus(NaOH P)and calcium combined phosphorus(HCl P)in the surface sediment were measured,and the distribution characteristics and pollution status of organic matter and nutrient salts in the surface sediment were analyzed.The results showed that the average mass ratios of OM,TN and TP in the sediment of Xinglin Bay Reservoir were 49360.28,1588.63 and 1095.63 mg·kg^(-1),respec-tively;the spatial distribution of OM,TN,EN and HN showed an increase and then a decrease from the confluence of Hou River to the estuary,and a gradual decrease from the confluence of Jiutian Lake and Dongren Drainage Canals to the estuary;the spatial distribution of TP,IP,NaOH P and HCl P showed a gradual decrease with the direction of water flow;the sediment had a high risk of nitrogen and phosphorus release,and was prone to eutrophication,of which,nitrogen mainly came from organic matter enrichment,phosphorus mainly came from phosphorus containing agricultural wastewater and residential sewage from upstream tributaries and the surrounding areas,and OM mainly came from higher plants;nitrogen,phosphorus single pollution index and comprehensive pollution index were in heavy pollution as a whole,nutrient salts pollution mainly came from nitrogen,organic index as a whole was still in clean level,and the sediment as a whole was polluted by organic nitrogen.